Word Study
cactus
CIDE DICTIONARY
cactus, n. [L., a kind of cactus, Gr. .].
Any plant of the order Cactacæ , as the prickly pear and the night-blooming cereus. See Cereus. They usually have leafless stems and branches, often beset with clustered thorns, and are mostly natives of the warmer parts of America. [1913 Webster]
OXFORD DICTIONARY
cactus, n. (pl. cacti or cactuses) any succulent plant of the family Cactaceae, with a thick fleshy stem, usu. spines but no leaves, and brilliantly coloured flowers.
Idiom
cactus dahlia any kind of dahlia with quilled petals resembling a cactus flower.
Derivative
cactaceous adj.
Etymology
L f. Gk kaktos cardoon
THESAURUS
cactus
bramble, brier, bristle, burr, catchweed, cleavers, goose grass, needle, nettle, pine needle, prickle, quill, spicule, spiculum, spike, spikelet, spine, sticker, thistle, thorn, yuccaFor further exploring for "cactus" in Webster Dictionary Online